<!DOCTYPE html>
<head>
    <title>Document</title>

    <script src="./index.js"></script>
    <link rel="stylesheet" type="text/css" href="./index.css" /> 
</head>
<body>
    Hello World !<br/>
    <a class="title">引用外部样式</a> <br/>
    <button onclick="invokeJs()">调用外部js</button>
</body>
</html>